High impact ribbons

ABSTRACT

HIGH IMPACT RIBBONS COMPRISE A TRANSFER LAYER OF A POROUS RESIN MATRIX CONTAINING EXPRESSIBLE INK AND A SECOND POLYMER FILM BACKING LAYER COEXTENSIVE WITH AND BONDED TO THE BACK SURFACE OF THE TRANSFER LAYER BY A THIN INTERMEDIATE LAYER OF ELASTOMERIC ADHESIVE POLYMER.

Aug. 8, 1972 H T. FINDLAY HIGH IMPACT RIBBONS Filed Feb. 17, 1970 FIG. 3

STERRITT R. FULLER,JR. JERRY F. STONE BY MM M ATTORNEY.

by a thin intermediate layer United States Patent O U.S. Cl. 161160 1 Claim ABSTRACT OF THE DISCLOSURE High impact ribbons comprise a transfer layer of a porous resinmatrix containing expressible ink and a second polymer film backing layer coextensive with and bonded to the back surface of the transfer layer by a thin intermediate layer of elastomeric adhesive polymer.

BACKGROUND OF THE INVENTION This invention relates generally to transfer media and more particularly to typewriter ribbons having a porous polymer matrix transfer layer.

Certain problems exist in the area of plastic matrix typewriter ribbons. For example, reuseable matrix ribbons show either breakdown of the polymer matrix or cutting of the backing layer prior to ink depletion. Cut resistance can be improved by increasing the caliper of the ribbon but this has the eifect of degrading the print quality. The transfer of large solid particles of the ribbon to the copy paper, which results in a significant distortion of the type face imagev known as picking, ranges from a moderate to a severeproblem. Also, separation of the porous layer from the support layer sometimes occurs .prior to depletion of the ink such that a portion of the ink is wasted.

BRIEF DESCRIPTION OF THE INVENTION In accordance with this invention, a transfer medium has been found which has unexpectedly superior properties of cut and pick resistance. The transfer medium comprises a porous resin matrix transfer layer containing expressible ink in the pores and a backing layer coextensive with and bonded to the back surface of the transfer layer of an elastomeric polymer adhesive. 2

DESCRIPTION 0F THE DRAWINGS FIG. 1 is a cross sectional view with parts broken away ice 2 DETAILED DESCRIPTION Elastomeric adhesives are sandwiched between a matrix transfer layer and a supporting layer. Suitable matrix transfer layers are well known in the art and are described, for example, in United States Patents 3,403,184 and 3,413,183. Suitable support layers are, for example, polymer films or other flexible materials which will give good conformation to a typeface. With this approach, the impacted adhesive material is capable of stretching along with the polymer layers. This assures continuous adhesion under the most extreme conditions of elongation at point of impact. Non-elastic adhesive materials such as parafiin wax or the dual use of solvent employed in the prior art give poor results in this regard.

Therefore, adhesives with relatively high elastomeric properties, for example, acrylonitrile-butadiene, ethylene acetate copolymer, polyisoprene, polybutylene, styrenebutadiene copolymer and mixtures thereof can be successfully employed as an adhesive layer between the support film and porous layer. Particularly, advantageous results occur when the adhesive is an acrylonitrile-butadiene polymerwith a nitrile content of about 15-45 percent by weight or a combination of acrylonitrile-butadi- .ene mixed witha styrene butadiene copolymer. Useful adhesive polymers are adhesive materials which without plasticization and within the temperature range of 10 C. to C. are capable of large deformation upon the application of stress without rupture and which can recover spontaneously and almost completely upon removal of Performance is excellent with respect to adhesion up to and beyond the elastic limit of the polymer comprising the matrix and backing layers. However, it is also observed that unexpected cut and pick resistance is obtained. The magnitude of the improvement is demonstrated by comparing low impact nylon matrix ribbon material with high impact porous nylon ribbons of this construction. Low impact nylon matrix ribbon material is designed for limited overstrikes on a typewriter and this ribbon material in high impact applications quickly breaks down. However, it is found that when the material is sandwiched with an acrylonitrile-butadiene adhesive to a nylon support layer, the ribbon performed on the level equivalent to the best high impact ribbons previously known. Therefore, ribbons have been considered impossible to use in high impact applications now are adequate when the ribbon structure is modified according to this invention. As an illustration the following comparison of a ribbon of the invention. 50 can be drawn as shown in Table I.

TABLE I No. of over strikes Results A Low impact n'ylon matrix ribbon 3 Cuts, picks, folds,

embosses. B Low impact nylon matrix layer plus parafiin 10 Do.

wax adhesive plus nylon 6 film backing.

C. Low impact nylon matrix layer plus aery- 25 No cutting, no picking, I lonitrlle butadiene adhesive plus nylon 6 no bfgggiillllg, reduced em g.

film backing layer.

Sample A was a low impact nylon matrix ribbon prepared in accordance with the process described in US. Patent 3,413,184 having a nylon backing layer solvent coated onto the ribbon and a caliper of .0013 inch. Sample B consisted of a low impact nylon matrix layer .0013 inch in thickness bonded by a paraflin wax adhesive layer .0005 inch in thickness to a nylon 6 film backing layer .0015 inch in thickness. Sample C consisted of a .0013

inch thick low. impacttnylo'n' matrix layei'bolldedke a i 1.5-inch. thick-gym filmibagking 'laygribyeanintgmlga 'As illustfzrtdimFI'GfBf approximately /2"mil of'acrydiate layer .0005 inch in thickness of an acrylonitrile-butadiene .polymer adhesive. The structure of sample C is lonitrile-butadiene 24 was applied to a /2 to 1 mil nylon 6 film 23. As in Example 1, prior to windup, the nylon and Shown i F section in 1 y is the nylon nylon matrix bonded roll 27 was fed into the roll nip t whlch is d the yl m fi nbbon 13 29. The nylon, 6, side of thenylon and nylon matrix mahe? layer l I L terial was so plicedthat contact wa s-nlade andbonding tests were f fl 3 M9 type occurred with'the acrylonitrile butadiene"bated side of writer' at an impact setting of A fora sm'gle sheet. As w y oatednylon m that? shown in the table,-rib bon' samples' A and B" are inade- 10 bon i f wfi'i 'p dpf" quate for high impact applications because of any onejof I the listed failures of cutting, pickingand folding. Sample 'E k 3 C which has the structure of'the inventio'n'was adequate all p p fi Diffefefices ill l i l between In order to illustrate a--two=component adhesive intersample B and C are relatedto the change in adhesive 15 mediate ,layer. whiqh significantly upgrades .cutting per- -layerfrom parafiin-wax to an 'acrylonitrile-butadiene'elasformance," n"acrylonitrile butadiene (Chemig um N6l2B tomeric polymeL'The -i1ylon6-film stretches beyond-the :Goodyear Chemical-Company) iof a relatively lo limit of the wax adhesivelayer at the point of type irnleculai'wweight polymerof 'medium nitrile"'content (22% pact. Thus, onlythe nylon 6 film andthe adjacent. sur- I .to. 36% waszused in combination with a styrene-butaface of the nylon matrix layer remain in contactfunder ,diene polymer .(PlioliteSSA Goodyear Chemical-Coni- "the extremes of stretch and impact. Therefore, the paratpany).,The two adhesive materials were blended in to-lufin adhesive breaks'down' and fpicking beco'mes increasene by mixing 20 parts by weightof acrylonitrile-buta- *ingly' evident'withrepeated use. The unexpecte'd r'iovel diene and 4 parts by weight ofstyrene-butadiene into 76 picking improvement is, therefore, related to ,the "use 7 parts by v'veightfof'v toluene .iby-highpedstirring until 'of anelastomeric adhesive intermediate layer. I 25 the polymers were d,issolved, Two-three ply, ribbonsam- Subjective tests under extreme conditions of typingtl'ius 'ples were prepared using the above adhesive solutionin produced superior results in print, embossing'and'colufiin accordance with the procedures "describedwin. Examples strengthover commercial type polymer matrix 'ri bbonsof l augi The first sample had'as a'baclting layer. apolysimilar caliper." It is believed that the elastic-layers and urethanfilm Tuftane 310- B.'E. Goodyear. Chemical the successive film layers complement each'other to ab- Company) andalow impact nylon matrix ribbon and the sorb the shock of type impact and yet permit good'type second'fhas asj -,jb'acking layer'a rubber hydrochloride face conformity and elastic recovery. Elastomerie bind- (Pliofiln NW oodyearChemical'Company) and new ing layers of between about .0001 to .00l0 inchin thickimpact nylo" fix ibbon. The pertinent performance ness can be conveniently used. jdata'isshow TableII. 1 "Y I 'MBLE'II I p j Tuftane s10 .Bliofilm MW Tuftane3l0 cmflgiiil chemi I p p 7 plus N612B lus; NGIZBEKI?! Ghemigum Pliolite Pliolite v t N6l 2B 85A a Cutting anon Char/1n (u None I Picking 165 None None out test dev.'.. e 21 23+v 2 Column strength, 9 i2 90 Callper mil l.

1 Very severe. {Very slight.

The foregoing features of the invention. are furthereil- I Example 1 A nylon matrix ribbon of 0.0013" caliper was prepared in roll for m 15 as described in Patent 3,413,184 Exa mple TI A 20% by weight solution of acrylonitrile-biitadiene 17 (Chemigum #608 from Goodyear Chemical Co.) in

toluene was prepared. Following standard coating anddryr. l

the matrix layer on each side by intermediate elastomeric ing procedures, a /2 mil layer of acrylonitrile-butadi'en'e (after drying) was deposited on the nylonbacked surface of the matrix ribbon as illustrated in FIG. 2! After'dryi the acrylonitrile-butadiene deposit with hot';airfand,'pr1 0 polymer, layer was found to be critical because although placement of the relatively stiif copolymer layer in the out side backing position was found to give the desired dimensional stability, it resulted in an unsatisfactory print the nip of take-up roll 21. The tacky 'sniraceor the acrylonitrile-butadiene bonded itself to the nylon 6 film.

.The roll 19 of bonded nylon and nylon matrix was slit to U the width of typewriter ribbons without furtherprocessing. "70 ;-,The foregoinghas described novel matrix-mibbon con- As a preferred structure, one more additional bonded .layer is added to the ribbon because of the significant additional gain which is realized in cut resistance as illusare preferentially coated independently.

intensity due to a lack of conformity of the ribbon with structions which overcome the disabilities previously. encountered with the ,relatively: soft nylon matrix ribbons. Elastomeric. adhesive-not only insuringa good bond between the supporting film and the matrix layer but the ribbons'of' the invention have outstanding and unexpected cut and pick resistance improvement. Accordingly, standard low impact nylon matrix ribbons are upgraded to a non-picking structure when incorporated into the invention. Additionally, the expected broading of print usually associated with high caliper, 0.003" or more ribbons, is not observed in the ribbon structures prepared in accordance with the invention which is believed to be a function of the compressibility of the binders employed in the invention.

We claim:

'1. A transfer medium comprising a porous resin matrix transfer layer containing expressible ink and a polymer film backing layer coextensive with and bonded to the back surface of said transfer layer by a 0.0001 to 0.0010 inch thick intermediate layer of an elastomeric polymer adhesive wherein said resin matrix layer is nylon and said adhesive is acrylonitrile-butadiene.

References Cited UNITED STATES PATENTS 10 ROBERT F. BURNETT, Primary Examiner R. A. DAWSON, Assistant Examiner US. Cl. X.R.

ll736.l, 36.4; l56--331, 334; 161165, 227, 255; 

